Vacuum apparatus for investing patterns



Patented Febyzs, 1941 2,415,506.' i

UNIrE-D :PATENT PATTERNS vJoe R. Vest, Phoenix, rizgasslgnor of fifty per cent to Edward Burrall, Phoenix,

Application' october s, (19,44, smerige: 557,520

My invention relates paratus for investing wax patterns,.under `vac*- uum, with plaster composition, for subsequent use in"metal castings, for in stance,"'in dental to improvements inf al!A F 2 claims. ,(cl. 27279);

sealing means fora-,bell jar 3.,.adapted to sur mount saidpad. Thebell jar Sis provided with a widened flat rim 4 adapted tolt flat vonsaid pad to form therewith an .air-tightsealaround.

work, the manufacture of jewelry andthe like. 5 the rimofsaidjar.- The top of the jar3 is/profk As is well known, in in'vestingsuch 'patternsv vided with.asuitable,handle-forming'knolj5. .A and mixing'the plaster composition,v air bubbles vacuum line: E extends from thetop of said `jar3 are liable to occur in the composition which/cling for'connectionto a suitable vacuum pump, not to the patterns and result in afrough casting covshown. An yair inlet valve is provided in the top ered with small metal protuberances, th'edisad- 1o of said jar 3, as at l. `Within thebell jar.3,is a vantage of which will be manifest. `Also, withAk relativelysmaller inner bell jar 8 having an open-y complicated jewelry patterns having cavities and ing 9 in thetop thereof. A substantally'conical, crevices therein, investing ,with present `day ap- `rubber container Illfor plaster composition1 not paratus is frequently unsatisfactory because/"the shown,extends`part way ,into said jar 8 througnplaster composition does .not enter. such cavities l5 the opening 9 andvistted in said openingand and crevices. Y l.providedwith a downwardly flaring, circumfer With the foregoing'in mind', the-'primary object,A ential rubber flap I I 4iittin'g'over the top-'of saidl of my invention is to provide highly efficient, sim-Vv Jar 8 to forman air-,tight seal around the opening ply constructed and 'comparatively inexpensive 9. The rcontainer/I U, at its lower end,'terminate's vacuum. apparatusr for investing wax patterns 2o in a" slit, rubber discharge nipple I2 normally' with plaster compositions, regardlessv of thecharcfosed andadapted to expand and thus open, acter of the patterns, so as to obviate theforma- A fflxed, rubber seat' I3 of disc-like, 'nat-top tion' of air bubbles and properly introduce the i form supports the inner bell jar 8, the lower rim` plaster composition into cavities, crevices, and of which is also widened and flat to form with Vthe like. l. l 25 said .seatan air-tight seal; around said rim,l V

Other and subordinate objects arealso compre- The seat I3 is a particular feature y of niy'invenhA hended by my invention, all of which, .together tion, said seat having a convex bottom, I4 formwith the precise nature of my improvements, will ing a feathered, readily flexible edge I5 around vbe readilyunderstood when the succeeding de-k the lower rim of said jar 8 which functions, as,` l scription and claims are readv'vith referenceto 30,Wi11presently more clearlyv appear, yasa valve for.;A l the drawings accompanying and forming part 'of opening yand closing thebottomfoffsaid jar 8:. i. this specification. f 2 f Radial, flat-bottom ribs I6 are provided on the Insaid drawings: y: bottomof rthe seat I3v for fitting iiat onA armetal Figure 1 is a view in vertical section of 'myimf seat-supporting disc Iljlmposed on .the pad; l proved apparatus, ina' preferred'embodiment 35 concentricallythereof and within the bell' jarJI. thereof, f A tubular air` inlet valve casing I8v extends Figure 2 is a view in top plan, and drawn to 'axially through the base I,pad 2, disc I'I and seat an enlarged scale, I3 and maintainsthe same in concentric rela' Figure 3 is a fragmentary view in transverse tion. The valve casing I8 forms anaxial partv section taken on the line 3-3 of Figure 2, and 40 of a flask-supporting disc I9 imposed on the Vseat drawn toafurtherenlargedscale, i t, I3 within the inner jar 8 for supporting the Figure 4 is a View in bottom plan 0f the Sea-t fOr usual flask 20 adapted toi contain the` waxpatthe inner bell jar, drawn to an`enlarged scale. terns, not shown.` The valve casing I8 is provided 1 Figure 5 is a fragmentary view in vertical secat its upperend with radial ports, as at kv2 I', which tion of the `container andinner bell jar, 45 open into radial air discharge grooves 22 proy Figure 6 lis a view in vertical section taken on vided in the bottom of the disc I9. A valve 23 the line 6-6 of Figure 1 and drawn to an enseatsdownwardly ina seat 24 in the valve casing larged scale, I8, with a stein. 25 extending outI of the lower end i Figure '7 is a view in bottom plan ofthe flaskof said casing. A coil spring 2B in said casing I8 supporting disc and air inlet valve. 50 interposed between the valve 23 and a threaded I f V` Referring to the drawings by numerals, in the closure plug 21 for the end of said casing, norillustrated, preferred embodiment thereof, my mally seats said valve A nut 28turned onto the improved apparatus comprises a disc-like base I lower end of the valve casing I8, together with. i u of Wood, preferably, supporting thereon a concenthe disc' I9, Aclamp the base I, pad 2, plateI'I, seat f l tric, relatively smaller rubber pad 2 forming a 85 I3 and the disc'IS in assembled relation. o

,ormai *I r.All suitable hand lever 29 is p1voted, as at 30,

I on the bottom of the base l for moving the valve when this is accomplished, the vacuation opera-1, tionis stopped. In the process of establishing ai substantially complete vacuum in the inner bell` Thus the vacuum in both jars is equalized and,v

jar 8, all air is removed from the plaster com#r l position. Next,A a small amount of atmosphericV airis introduced into the bell vjar 3 through the` medium lof the air inletr valve'l so that there isj a greater vacuum in thev inner belly jar 8 which` tends, under the *suction in said inner jar, to

drawthe edge I5 of the seat I3 into sealing,v relation with the bottom rim of said inner jar. With,v

this condition obtaining in saidinner jar 8, the;

plaster is drawn through the nipple l2 and enters l all cavities and crevices in the patterns without the formation of any air bubbles inthe plaster composition or on thepatterns. When the plaster composition passes through the nipple l2, air passes vfrom the bell jar r'3 into the inner bell Vjar` 8 and the air pressure inboth .lars` is'equalized.` The air inlet valve 'l may then be opened to` achieve atmospheric pressure in bothjjarsl and the flask 20 removed.V At anytime during dislcharge ofthe plaster'composition from the nipple I 2,2the'hand lever 29 may be operated to unseat the valve 23 andadmit atmospheric air into the inner belly jar 8 by way of the valve ycasing I8, l

ports 2| an'd air inlet grooves 22thus stopping the flow of plaster composition from the con-g tainerl whenv the' desired quantity vof plaster composition has been deposited in saidv flask 20.

vThe foregoing will, it i's believed, suflice to im part a clear understanding of `my invention without further explanation. t

`Manifestly, the invention, as described, is susceptible of Amoditication without departing from the inventive concept, and right is herein reserved to such modifications as lfall within the scope of the appended claims.`

l What I claim is: ,n

1, Vacuum apparatus for investing patterns Vin a. ilask with powder composition comprising an outer bell jar, means for supporting said -jar and forming under a vacuum created in said jar a seal around the rim of the jar, an inner bell jar in the outer jar, a composition container extending into said inner jar through the top thereof and provided with a discharge endadapted to be` -distended under the action of vacuum created in the inner vjarto 'discharge composition therefrom,

-a seat for said inner jar adapted under the action of a vacuum in the inner jar tc seal the same and under a vacuum in the outer jar with air pressure'in the'inner jar to open said inner jar, K

a vacuum line extending from they outer jar* for connection `to a vacuum pump to evacuate the air from `said jars and create a vacuum therein. an air valve'for admitting atmospheric air to the". outer jar to break the vacuum therein and cause said seat to seal the inner jar, and means for'supporting a pattern ask in the inner jar, said seat comprising a disc-like member of resilient material provided with. a featherededge underlying the'frim ofpsaid inner bell jar.

.2. Vacuumjapparatus for investing patterns i comprising an -outer bell jar, an inner bell jar` having an open top and bottom, a flask in said inner bell jar, a composition container extending part way into the inner bell jar andclosing the top of the same, said container having a normally closed discharge end adapted to Aopen under the inuence of a vacuum in said inner bell jar and discharge Vcomposition into said flask, means to establish a vacuum in said outer and inner bell jars comprising a vacuum line to said outer bellv jar, anda member4 normally A closingthe bottom of the inner bell jar and having a part flexible underthe inuenceof a vacuumvin the outer bell jar toopen said bottom andI establish communication between said jars, and means to break the vacuum in the outer bell jar to cause the vacuum in the inner bell jar to open said dischargeend ofsaidcontainer.I

` JOER. VEST.

s REFERENCES CITED i l The following referenCes'are vrof `record in the flle of this patent: 'f j ,i

UNITED lSTATE?, PATENTS 1,325,004 Davidson 'Dec. 16,1919 

